$$$\mathrm{}$Fantasia is a popular photographer in her area and she typically charges $$125$for a photo session. Mario is an accountant who charges $$100$ per hour to complete a tax return. Fantasia would like to have her tax return prepared and wants to exchange her photography services for Mario$$s work on her tax return. Mario estimates that it will take about $4$ hours to complete the tax return. They agree to four photo sessions of Mario$$s children. How much income, if any, must Fantasia include in her income?